Sensitization of Gastric Cancer Cells to 5-FU by MicroRNA-204 Through Targeting the TGFBR2-Mediated Epithelial to Mesenchymal Transition

Abstract

Background/Aims: Gastric cancer (GC) is the most common gastrointestinal malignancy, causing cancer-related deaths in East Asia. MicroRNAs (miRNAs) are small non-coding RNAs aberrantly expressed in human tumors. In this study, we aim to investigate the roles of miR-204 in the epithelial to mesenchymal transition (EMT)-associated chemosensitivity. Methods: The expression of miR-204 was detected in clinical tumor samples and GC cell lines by real time PCR. Tumor cell’s growth, invasion, and migration were measured by MTT assay, wound healing assay, and transwell invasion assay, respectively. Western blot method was used to detect the protein levels of indicated genes. Luciferase reporter assay was performed to validate the target gene of miR-204. The in vivo role of miR-204 was measured using a xenograft mouse model of GC. Results: By comparing the expressions of miR-204 in human gastric tumors and their adjacent normal tissues, it was disclosed that miR-204 was significantly downregulated in gastric tumors. Moreover, miR-204 was downregulated in multiple GC cell lines compared with normal gastric epithelial cells. Overexpression of miR-204 suppressed GC cells’ proliferation, invasion, and migration. It is noteworthy that 5-FU treatments induced miR-204 expression and suppressed TGF-β pathway. By establishment of 5-FU resistant GC cell line, it was revealed that miR-204 was significantly downregulated in 5-FU resistant GC cells, representing mesenchymal features with downregulation of epithelial marker, while mesenchymal markers were upregulated. We identified TGFBR2 as a direct target of miR-204 by Western blot method and luciferase assay in GC cells and tumor samples as well. In addition, overexpression of miR-204 sensitized GC cells to 5-FU in vitro. Xenograft experiments demonstrated that the combination of miR-204 and 5-FU efficiently inhibited tumor growth and improved survival rate of mice as well. Eventually, we illustrated the restoration of TGFBR2 in miR-204 overexpression GC cells, which recovered resistance to 5-FU treatments compared with miR-204 overexpression GC cells. Conclusion: This study describes a miRNA-based therapeutic strategy against 5-FU resistance in GC, contributing to the development of anti-chemoresistance therapeutic agents.

Circulating microRNA146b‐5p is superior to C‐reactive protein as a novel biomarker for monitoring inflammatory bowel disease

“…In the discovery cohort, patients with clinically active IBD were recruited to detect the serum levels of 17 candidate miRNAs. MiR‐197‐5p, miR‐603, miR‐145‐3p, miR‐34a‐5p, miR‐323a‐3p, miR‐574‐3p, miR‐193b‐3p, miR‐31‐5p, miR‐27a, miR‐27b, miR‐944, miR‐204‐3p, miR‐141‐3p, miR‐206, miR‐24‐1‐5p, miR‐135b‐5p and miR‐146b‐5p were chosen from our miRNA microarray data for colonic tissues (Figure S2) and confirmed as candidates based on the results of published studies . The specific protocol used to select these miRNAs is shown in Figure S3.…”

Cisplatin resistance in gastric cancer cells is involved with GPR30‐mediated epithelial‐mesenchymal transition

“…EMT‐expressing cancer cells showed decreased expression of epithelial cell markers such as E‐cadherin and ZO‐1, while expression of mesenchymal cell markers such as vimentin and N‐cadherin increased. Although there is increasing evidence that EMT is closely related to the development of drug resistance in gastric cancer cells, its underlying mechanisms have not yet been fully elucidated …”

“…Although there is increasing evidence that EMT is closely related to the development of drug resistance in gastric cancer cells, its underlying mechanisms have not yet been fully elucidated. [14][15][16] To date, many studies have investigated the role of oestrogen receptor (ER) in gastric cancer, and the possible mechanisms of these effects and the clinical relevance of dysregulated ER in GC.…”

Noncoding RNAs in gastric cancer: implications for drug resistance

“…Additionally, exogenous expression of miR-197 and miR-BART15-3p could also strongly promote 5-FU chemosensitivity through down-regulating expression of mitogenactivated protein kinase 1 (MAPK1) and Tax1-binding protein 1 (TAX1BP1), respectively [134,135]. Tumor suppressor miR-195-5p, miR-204, miR-623, miR-939 and miR-124 have been shown to be involved in overcoming 5-FU resistance of gastric cancer via silencing Zing finger 139 (ZNF139), TGFBR2, cyclin D1 (CCND1), solute carrier family 34 member 2 (SLC34A2) and EZH2, respectively [136][137][138][139][140].…”